What is the best database to track users relations?

Question

I need to track users relations in a social app, something like this:

UserA follow UserC, UserD, and UserE
UserZ follow UserC, UserD, and UserE
UserC follow UserA, UserD, and UserE

And so on.

First, I need a partition tolerant database so MySQL and its brothers are out of the game.

I look at couchdb but it creates a revision for each change, so, if your doc is like:

{
  uuid: uuid
  name: name,
  lastName: lastName
  follows: [ uuid1, uuid2, uuid3 ]
}

you will have this other revisions in the data base

(rev 1)
{
  uuid: uuid
  name: name,
  lastName: lastName
  follows: [ uuid1, uuid2 ]
}
(rev 2)
{
  uuid: uuid
  name: name,
  lastName: lastName
  follows: [ uuid1 ]
}

That is a lot of space, I know you can free this by some manual action but the problem don't disappear.

I look at Cassandra, and so far it looks like a good solution, it allows insertions with no extra space issues like couchdb. I can create a key space, then a column and then an store relations, something like this:

keyspace:{
  column:{
    ...
    uuidT:{ uuidA: timestamp, uuidB: timestamp, uuidZ }
    uuidF:{ uuidA: timestamp, uuidB: timestamp, uuidZ }
    uuidH:{ uuidA: timestamp, uuidB: timestamp, uuidZ }
    ...
  }
}

But I'm wondering if a graphical database is best for this.

Edit:

After surf for a answer I found this page that helps to chose a DB. http://nosql.findthebest.com/

Actually I love all the couchdb magic, if you now a way to implement this in couchdb tell me — Delta, Jul 20 '12 at 04:39
There's no way around the need to compact your DB in Couch. Where you see a manual action, I see a set-and-forget cron job. — smathy, Jul 20 '12 at 20:08
I just updated my answer, [you can limit the number of revisions CouchDB keeps](http://wiki.apache.org/couchdb/HTTP_database_API#Accessing_Database-specific_options) — smathy, Jul 21 '12 at 21:47

score 2 · Answer 1 · answered Jul 21 '12 at 18:33

CouchDB is meant as an offline DB.

I would suggest looking into a graphDB, neo4j comes to mind. I was introduced to it via Mozilla labs in Toronto a few weeks ago, the people there told me it was the least painful graphDB to get up an running (you can apt-get/brew it). You can make arbitrary relationships in it, however it doesn't partition. If you want a DB that you can rely on and you want to do arbitrary relationships, maybe Titan is worth looking at.

smathy · Accepted Answer · 2012-07-21T21:46:34.527

FWIW, in CouchDB I always use arrays of objects, rather than just arrays of IDs. Eg.

{
  uuid: uuid
  name: name,
  lastName: lastName
  follows: [ { _id: uuid1 }, { _id: uuid2 }, { _id: uuid3 } ]
}

This is for two reasons:

It allows you, if you want, to easily add other join data to that object that you might want. Eg. { _id: uuid1, followed_on: "2011-10-22" }
It fits in nicely with the include_docs=true options for grabbing the associated doc in your view queries.

Update

Hey, check it out, you can limit the number of revisions kept in the DB

What is the best database to track users relations?

2 Answers2

Update